Lists

Hold a bunch of related values in one variable.

Counting starts at 0, so the first item is at index 0.

Square brackets, values separated by commas.

names = ["Steve", "Becca", "Alex"]
print(names)

Output

['Steve', 'Becca', 'Alex']

The index goes in square brackets.

names = ["Steve", "Becca", "Alex"]
print(names[0])
print(names[1])

Output

Steve
Becca

-1 is the last one, no matter how long the list is.

names = ["Steve", "Becca", "Alex"]
print(names[-1])

Output

Alex

len() gives how many are in the list.

names = ["Steve", "Becca", "Alex"]
print(len(names))

Output

Assign straight to the index.

names = ["Steve", "Becca", "Alex"]
names[1] = "Yara"
print(names)

Output

['Steve', 'Yara', 'Alex']

Use this one

append() is the one you will use most.

names = ["Steve", "Becca", "Alex"]
names.append("Yara")
print(names)

Output

['Steve', 'Becca', 'Alex', 'Yara']

Everything from that spot on shifts over.

names = ["Steve", "Becca", "Alex"]
names.insert(2, "Yara")
print(names)

Output

['Steve', 'Becca', 'Yara', 'Alex']

pop() with nothing inside takes the last one.

names = ["Steve", "Becca", "Alex"]
names.pop()
print(names)

Output

['Steve', 'Becca']

Give pop() an index to pick which one.

names = ["Steve", "Becca", "Alex"]
names.pop(0)
print(names)

Output

['Becca', 'Alex']

remove() takes the value itself, not the index.

names = ["Steve", "Becca", "Alex"]
names.remove("Becca")
print(names)

Output

['Steve', 'Alex']

name holds a different item each time around.

names = ["Steve", "Becca", "Alex"]
for name in names:
    print(f"Hi, {name}!")

Output

Hi, Steve!
Hi, Becca!
Hi, Alex!

in and not in give back True or False.

names = ["Steve", "Becca", "Alex"]
if "Becca" in names:
    print("Becca is here.")
if "Yara" not in names:
    print("Yara is not here.")

Output

Becca is here.
Yara is not here.